Sacroiliac joint fusion system

Abstract

A sacroiliac joint screw has a screw body having a head and a treaded shank with a self-drilling cutting tip. The screw body is cannulated and configured to receive a Steinmann pin for the purpose of a minimally invasive approach (MIS) for delivery to the sacroiliac joint (SI) while minimizing soft tissue damage. The self-drilling cutting tip creates a pilot hole. The threaded shank has a plurality of spiral cutting flutes, the spiral cutting flutes extend along a length of the threaded shank and are configured to provide a constant self-tapping feature. A plurality of bone harvesting windows are positioned in the spiral cutting flutes and are configured to pull in bone as the screw is advanced into the joint.

What is claimed is: 
     
         1 . A sacroiliac joint screw comprises:
 a screw body having a head and a threaded shank with a self-drilling cutting tip, the screw body is cannulated and configured to receive a Steinmann pin for the purpose of a minimally invasive approach (MIS) for delivery to the sacroiliac joint (SI) while minimizing soft tissue damage.   
     
     
         2 . The sacroiliac joint screw of  claim 1  wherein the self-drilling cutting tip creates a pilot hole. 
     
     
         3 . The sacroiliac joint screw of  claim 1  wherein the threaded shank has a plurality of spiral cutting flutes, the spiral cutting flutes extend along a length of the threaded shank and are configured to provide a constant self-tapping feature. 
     
     
         4 . The sacroiliac joint screw of  claim 3  wherein a plurality of bone harvesting windows are positioned in the spiral cutting flutes configured to pull in bone as the screw is advanced into the joint. 
     
     
         5 . The sacroiliac joint screw of  claim 1  further comprises:
 an integrated removable tower for soft tissue protection, the tower being fixed at a proximal end of the screw. 
 
     
     
         6 . The sacroiliac joint screw of  claim 1  wherein the screw head has a reverse threaded external head geometry configured to allow a rescue tower to attach to the screw for screw removal. 
     
     
         7 . The sacroiliac joint screw of  claim 6  wherein the reverse threaded external head geometry is a left-handed thread which allows loosening of the screw. 
     
     
         8 . The sacroiliac joint screw of  claim 1  wherein the screw head has an undercut on a distal side of the head, the undercut allows for a stab and grab attachment to a driver. 
     
     
         9 . The sacroiliac joint screw of  claim 1  wherein the screw has a secure threaded post-fill bone graft delivery tube mechanism to provide bone graft material. 
     
     
         10 . The sacroiliac joint screw of  claim 1  further comprises:
 a driver with a hexalobular drive configured to be received in an hexalobular drive aperture in the screw head. 
 
     
     
         11 . The sacroiliac joint screw of  claim 1  wherein the screw is made of a titanium alloy. 
     
     
         12 . The sacroiliac joint screw of  claim 1  wherein the screw is made in diameter sizes of 8.0 mm to 12.0 mm. 
     
     
         13 . The sacroiliac joint screw of  claim 12  wherein the screw is made in lengths from 25 mm to 60 mm. 
     
     
         14 . The sacroiliac joint screw of  claim 1  further comprises:
 a load dispersion cap attached to an underside of the screw head, the cap disperses the surface load and is configured to pivot and spin underneath the screw head. 
 
     
     
         15 . A method of sacroiliac joint fusion comprises the steps of:
 localizing the sacroiliac joint by fluoroscopy;   inserting a 2.8 mm Steinmann pin to the plane of the sacroiliac joint;   sliding dilator one over the Steinmann pin;   sliding dilator two over dilator one;   sliding dilator three over dilator two;   removing dilator one and inserting a screw depth gauge over the Steinmann pin;   reading a depth marking closest to the top of the Steinmann pin;   verifying the depth via fluoroscopy;   removing the screw depth gauge and dilator two to prepare for drilling;   selecting a desired drill bit size and drill to the depth reading indicated from the screw depth gauge;   attaching the appropriately sized sacroiliac screw to the physician's preferred driver and insert over the Steinmann pin;   threading until fully seated; a load dispersion cap should be threaded over the distal end of sacroiliac screw prior to threading/implantation if one is to be used;   removing dilator three and inserting a 14 mm or 16 mm parallel pin guide over the Steinmann pin;   using fluoroscopic imaging to align the parallel pin guide;   inserting a second Steinmann pin and repeating the steps above for any remaining sacroiliac screw;   threading in a graft filler tube to the sacroiliac screw and using a graft tamp to deliver any allograft or autograft of the physician's choice to the sacroiliac screw cannulation; and   removing all instrumentation and snapping the extension towers off the sacroiliac screws via a rocking motion.